Andrew Fowler

Plant Foods Consumed by Pan: Exploring the Variation of Nutritional Ecology Across Africa

It has been shown that differences in resource density and nutrient supply affect variation in ranging patterns, habitat use, and sociality. Among nonhuman primates, chimpanzees (Pan troglodytes) and bonobos (P. paniscus) have often been used as models for the link between social system and habitat ecology. Field reports suggest that resource density is higher in habitats occupied by bonobos (compared to chimpanzee habitats), and in the West (compared to the East) of the range of chimpanzees. In this study we compared diet quality at the level of species and populations using information from nutritional analyses of fruit and leaves consumed by chimpanzees (three) and bonobos (one population). Quality of plant foods was assessed on the basis of a) the concentration of macronutrients, fiber, and anti-feedants, and b) associations of different nutrient components. Overall plant samples collected at each site differed in terms of macronutrient content. However, nutritious quality and gross energy content of food samples were similar suggesting that dietary quality reflects selectivity rather than habitat ecology. The quality of plant foods consumed by bonobos was within the range of chimpanzees and the quality of plant foods consumed by western chimpanzees was not higher than that of eastern chimpanzees. While the results showed significant variation across forests inhabited by Pan, they did not match with geographical patterns between and within Pan species as proposed in previous studies. This suggests that the nutritional quality of the habitat is not always a reliable predictor of the quality of the diet.

Evidence for the consumption of arboreal, diurnal primates by bonobos (Pan paniscus)

We present evidence for the consumption of a diurnal, arboreal, group living primate by bonobos. The digit of an immature black mangabey (Lophocebus aterrimus) was found in the fresh feces of a bonobo (Pan paniscus) at the Lui Kotale study site, Democratic Republic of Congo. In close proximity to the fecal sample containing the remains of the digit, we also found a large part of the pelt of a black mangabey. Evidence suggests that the Lui Kotale bonobos consume more meat than other bonobo populations and have greater variation in the mammalian species exploited than previously thought [Hohmann & Fruth, Folia primatologica 79:103–110]. The current finding supports Stanfords argument [Current Anthropology 39:399–420] that some differences in the diet and behavior between chimpanzees (P. troglodytes) and bonobos are an artefact of the limited number of bonobo study populations. If bonobos did obtain the monkey by active hunting, this would challenge current evolutionary models relating the intra‐specific aggression and violence seen in chimpanzees and humans to hunting and meat consumption [Wrangham, Yearbook of Physical Anthropology 42:1–30]. Am. J. Primatol. 71:171–174, 2009.

Cannibalism in wild bonobos (Pan paniscus) at Lui Kotale

We describe the cannibalization of an infant bonobo (circa 2.5 years old) at Lui Kotale, in the Democratic Republic of Congo. The infant died of unknown causes and was consumed by several community members including its mother and an older sibling one day after death. Certain features concerning the pattern of consumption fit in with previously observed episodes of cannibalism in Pan, whereas others, such as the mothers participation in consuming the body, are notable. The incident suggests that filial cannibalism among apes need not be the result of nutritional or social stress and does not support the idea that filial cannibalism is a behavioral aberration. Am. J. Primatol. 72:509–514, 2010.

Leaf Surface Roughness Elicits Leaf Swallowing Behavior in Captive Chimpanzees (Pan troglodytes) and Bonobos (P. paniscus), but not in Gorillas (Gorilla gorilla) or Orangutans (Pongo abelii)

Researchers have described apparently self-medicative behaviors for a variety of nonhuman species including birds and primates. Wild chimpanzees, bonobos, and gorillas have been observed to swallow rough leaves without chewing, a behavior proposed to be self-medicative and to aid control of intestinal parasites. Researchers have hypothesized that the presence of hairs on the leaf surface elicits the behavior. We investigated the acquisition and the underlying mechanisms of leaf swallowing. We provided 42 captive great apes (24 chimpanzees, six bonobos, six gorillas, and six orangutans) with both rough-surfaced and hairless plants. None of the subjects had previously been observed to engage in leaf swallowing behavior and were therefore assumed naïve. Two chimpanzees and one bonobo swallowed rough-surfaced leaves spontaneously without chewing them. In a social setup six more chimpanzees acquired the behavior. None of the gorillas or orangutans showed leaf swallowing. Because this behavior occurred in naïve individuals, we conclude that it is part of the behavioral repertoire of chimpanzees and bonobos. Social learning is thus not strictly required for the acquisition of leaf swallowing, but it may still facilitate its expression. The fact that apes always chewed leaves of hairless control plants before swallowing, i.e., normal feeding behavior, indicates that the surface structure of leaves is indeed a determinant for initiating leaf swallowing in apes where it occurs.

New evidence for self‐medication in bonobos: Manniophyton fulvum leaf‐ and stemstrip‐swallowing from LuiKotale, Salonga National Park, DR Congo

The swallowing of entire leaves by apes across Africa without chewing has been observed for over 40 plant species. Here we add evidence for (a) a new site, LuiKotale where leaf‐swallowing of Manniophyton fulvum (Euphorbiaceae) is observed in bonobos, (b) a so far unreported ingestion of unchewed stemstrips of M. fulvum, we name stemstrip‐swallowing; and (c) a test of some of the requirements put forward by Huffman for the assessment of plants ingested for medical purpose. As ecological correlates we analyzed M. fulvum phenological data and examined 1,094 dung piles collected between 2002 and 2009. By that we assessed availability and choice of leaves. In addition, we provide the first full description of the behavior related to this plant species use by chimpanzees or bonobos using 56 bouts of M. fulvum ingestion observed between October 2007 and February 2010. With these data we tested and met 4 of the 6 requirements given by Huffman, supporting ingestion of this species as self‐medication. Despite species year‐round availability and abundance, M. fulvum was ingested only at specific times, in very small amounts, and by a small proportion of individuals per party. In the absence of our own parasitological data, we used M. fulvum swallowing as evidence for parasite infestation, and seasonality as a proxy for stressors underlying seasonal fluctuation and impacting immune responses. Using these indirect factors available, we investigated conditions for a parasite to develop to its infective stage as well as conditions for the host to cope with infections. Both rain and temperature were good predictors for M. fulvum ingestion. We discuss the use of M. fulvum with respect to its hispidity and subsequent purging properties and provide insight into its ethnomedicinal uses by humans, stimulating speculations about potentially additional pharmacological effects. Am. J. Primatol. 76:146–158, 2014.

Patriarchal Chimpanzees, Matriarchal Bonobos: Potential Ecological Causes of a Pan Dichotomy

Chimpanzees and bonobos, despite being closely related hominoid primates, differ in female gregariousness and dominance style. Violent male aggression is not atypical in chimpanzee societies and is vented against both other males and females in intra- as well as inter-group conflicts; relationships amongst females are rather weak. Bonobo societies, on the other hand, are female-centred; reports[Comp1] about inter-group conflict are rare to absent but there are numerous reports of blood-drawing injuries inflicted upon males by coalitions of females.

Hunters, Fire, Cattle: Conservation Challenges in Eastern Nigeria, with Special Reference to Chimpanzees

The historic range of the recently recognised fourth subspecies of chimpanzee, Pan troglodytes vellerosus, extended roughly between the Niger River in Nigeria and the Sanaga River in Cameroon. Most original habitat is lost, but a stronghold remains in the remote Taraba region of north-eastern Nigeria, in particular Gashaka Gumti National Park (GGNP). We explored the region’s conservation prospects for large mammals, and in particular chimpanzees, through foot surveys, for a total of 59 days. No evidence for chimpanzees was found in the Shebshi Mountains, which represent the potential northern distribution, but it is unclear if their historic range ever extended so far. The Cameroon border area and the Fali mountains that demarcate the southern distribution, and the vicinity of GGNP including the Mambilla Plateau, have experienced considerable deterioration of habitat. Surviving forests are often practically devoid of large mammals, as poaching and hunting are rampant, while patrolling and protective measures are all but absent. Forest destruction is progressive due to fire damage from seasonal bush burning and cattle grazing. It is thus unlikely that large chimpanzee populations survive outside GGNP. Whatever populations of chimpanzees may have been found there in the past have now either disappeared, are on the brink of extinction or reduced to small remnant groups. On the more positive side is the realisation that GGNP seems to fulfil its elementary function of providing a haven for threatened wildlife, including charismatic megafauna such as the chimpanzee. A contiguous population of about 1000 chimpanzees survives in the Gashaka sector of the park, in the axis Gashaka – Kwano – Yakuba – Chappal Wade (Nigeria’s highest peak). Nevertheless, it is the remoteness and large extent of the park, rather than effective protection measures, that have so far ensured the existence of the apes. In fact, the park’s chimpanzee habitat is also shrinking, particularly in and around the enclaves of settled pastoralists, due to cattle grazing, bush-burning, hunting and a lack of patrols. Community-based conservation approaches seem to have made little progress, and protective measures emanating from research activities are too localised. There is an urgent need for law enforcement, at least in the medium term, as conservation measures will otherwise be meaningless, given that little would be left to protect.

Monkeys and apes as animals and humans: Ethno-primatology in Nigeria's Taraba region

Nigeria’s remote Taraba region harbours a wealth of wildlife. This diversity has been greatly reduced in many locales. We explored local attitudes towards monkeys and chimpanzees through a questionnaire survey, with the goal of identifying factors that may aid conservation measures. This so-called ethno-primatological approach ultimately aims to mitigate the cultural and perceptive isolation of non-local conservationists and primatologists.

Panthropology of the Fourth Chimpanzee: A Contribution to Cultural Primatology

A trademark of Homo sapiens is the enormous variation in behavioural patterns across populations. Insight into the development of human cultures can be aided by studies of Pan communities across Africa, which display unique combinations of social behaviour and elementary technology. Only cross-population comparisons can reveal whether this diversity reflects differential genetics, environmental constraints, or arbitrary cultural patterns. However, the recently recognised and most endangered subspecies Pan troglodytesAU1 vellerosus remains completely unstudied in this respect. We report on the Nigerian chimpanzees at Gashaka. At this site, diet composition is highly varied and the apes have to cope with high concentrations of anti-feedant defenses of plants against consumption. It is not surprising therefore, that Gashaka chimpanzees use a varied tool-kit for extractive foraging. For example, they harvest insects throughout the year, employing digging sticks and probes to obtain honey from nests of stingless bees and honey bees, dipping wands to prey on army ants and fishing rods to eat arboreal ants. Tools appeared to be custom-made with a considerable degree of standardisation and preferential use of distal ends. Many of these expressions of subsistence xadtechnology seem to be environmentally constrained. Most notably, the absence of termite eating could reflect a low abundance of mounds. Other traits may represent arbitrary cultural variation. For example, two types of hard-shelled nuts found in the habitat are not opened with tools, unlike what is observed elsewhere in West Africa. The prevalence of elementary technology may indicate that the material culture of Gashaka chimpanzees is most closely related to core cultural tendencies of Central African populations of these apes.

Evolutionary Changes in the Craniofacial Morphology of Primates

s 343 Folia Primatol 2004;75:341–354 consumption is occasional or limited for Microcebus, Cheirogaleus and Mirza, gum is the dominant food source for Phaner and Allocebus. Craniofacial shape variations were analysed using geometric morphometrics: methods based on landmarks identification (Procrustes superimpositions) were chosen for skull shape analysis, and methods based on outline decomposition (elliptical Fourier functions) for the study of mandible shape. The morphospaces obtained at the level of the infraorder appear to be highly constrained by dietary habits, especially in the case of the mandibles. At the finer level of the Cheirogaleidae family, the analyses permit us (1) to separate craniomandibular shape variations associated with the two dietary categories and (2) among the omnivorous category, to distinguish the fluctuations associated with the percentage of gum consumption. Craniofacial Variation and Adaptive Diversity in Early Hominids: Some Morphometric Aspects